Evolved Packet System and Method for Processing Emergency Call Attachment Thereof

Abstract

The disclosure discloses an evolved packet system and a method for processing an emergency call attachment thereof, wherein the method comprises: a NodeB selects one PLMN from those Public Land Mobile-communication Networks (PLMN) supporting emergency calls according to an emergency call request message received from a UE which is in a restricted state; the NodeB sends information of the selected PLMN to the UE through a Radio Resource Control (RRC) connection establishment message; and the UE uses the information to establish attachment with the selected PLMN. In the disclosure, it can be ensured that the PLMN to which the User Equipment (UE) selects to attach supports an emergency call, and it can be ensured that Kasmes generated by the UE and the Mobility Management Entity (MME) are consistent during the Authentication and Key Agreement (AKA) flow, so that the success of the emergency call can be guaranteed.

1 . A method for processing an emergency call attachment of an evolved packet system, comprising:
 according to an emergency call request message received from a user equipment (UE) which is in a restricted state, a NodeB selecting one from a plurality of Public Land Mobile-communication Networks (PLMNs) supporting emergency calls;   the NodeB sending information of the selected PLMN to the UE through a Radio Resource Control (RRC) connection establishment message; and   the UE using the information to establish attachment with the selected PLMN.   
     
     
         2 . The method according to  claim 1 , wherein the NodeB sending information of the selected PLMN to the UE through an RRC connection establishment message comprises: the NodeB sending an index number of the selected PLMN in a PLMN ID list in a system message to the UE through an RRC connection establishment message, wherein the PLMN ID list is a list consisting of PLMN IDs of all PLMNs to which the NodeB is connected. 
     
     
         3 . The method according to  claim 2 , wherein the UE using the information to establish attachment with the selected PLMN comprises:
 the UE analyzing the index number from the received RRC connection establishment message;   the UE converting the index number into a PLMN ID;   the UE sending an RRC connection completion message carrying a Non Access (NAS) message to the NodeB;   the NodeB sending the NAS message to a Mobility Management Entity (MME) of the selected PLMN; and   the UE using the PLMN ID of the selected PLMN to generate a Kasme, and using the generated Kasme to verify authentication and key agreement with the MME to complete the attachment.   
     
     
         4 . A method for processing an emergency call attachment of an evolved packet system, comprising:
 according to an emergency call request message received from a UE which is in a restricted state, a NodeB sending information of a plurality of PLMNs supporting emergency calls to the UE through an RRC connection establishment message;   the UE selecting one of the plurality of PLMNs supporting emergency calls according to the information; and   the UE establishing attachment with the selected PLMN.   
     
     
         5 . The method according to  claim 4 , wherein according to an emergency call request message received from a UE which is in a restricted state, a NodeB sending information of a plurality of PLMNs supporting emergency calls to the UE through an RRC connection establishment message comprises: the NodeB sending index numbers of the plurality of PLMNs supporting emergency calls to the UE through an RRC connection establishment message. 
     
     
         6 . The method according to  claim 5 , wherein the UE selecting one of the plurality of PLMNs supporting emergency calls according to the information comprises:
 the UE analyzing the index numbers from the received RRC connection establishment message;   the UE converting the index numbers into PLMN IDs; and   the UE selecting one from the plurality of PLMNs identified by the PLMN IDs obtained through conversion.   
     
     
         7 . The method according to  claim 6 , wherein the UE using the information to establish attachment with the selected PLMN comprises:
 the UE sending the PLMN ID of the selected PLMN to the NodeB through an RRC connection completion message, wherein the RRC connection completion message carries an NAS message;   the NodeB sending the NAS message to a MME of the selected PLMN; and   the NodeB using the PLMN ID of the selected PLMN to generate a Kasme and using the generated Kasme to verify authentication and key agreement with the MME to complete the attachment.   
     
     
         8 . An evolved packet system, comprising:
 a NodeB, configured to, according to an emergency call request message received from a UE which is in a restricted state, select one from a plurality of PLMNs supporting emergency calls, and also configured to send information of the selected PLMN to the UE through an RRC connection establishment message; and   the UE, configured to use the information to establish attachment with the selected PLMN.   
     
     
         9 . The system according to  claim 8 , wherein
 the NodeB comprises a first sending module, configured to send an index number of the selected PLMN in a PLMN ID list in a system message to the UE through the RRC connection establishment message, wherein the PLMN ID list is a list consisting of PLMN IDs of all PLMNs to which the NodeB is connected, and also configured to send an NAS message in an RRC connection completion message from the UE to an MME of the selected PLMN; and   the UE comprises
 an analyzing module, configured to analyze the index number from the received RRC connection establishment message and to convert the index number into a PLMN ID; 
   a second sending module, configured to send the RRC connection completion message carrying the NAS message to the NodeB; and   an execution module, configured to use the PLMN ID of the selected PLMN to generate a Kasme and to use the generated Kasme to verify authentication and key agreement with the MME to complete the attachment.   
     
     
         10 - 11 . (canceled)